1. Field of the Invention
This invention relates to couplers for joining sections of pipe and more particularly to such couplers for joining or adding to sections of existing pipe where the existing pipe is relatively inaccessible or cannot be removed and replaced without substantial difficulty.
2. Background of the Invention
A wide variety of coupling devices have been developed for joining sections of pipe, including simple screw coupling or couplings which are adhesively-bonded or cemented to the pipe sections to be joined. In some cases pipes are installed in walls or underground or under floors or cement so that such pipes are relatively inaccessible and it would be very expensive to remove and replace such existing pipe. Where leaks occur in such pipe or where it is desired to add to the existing pipe of this type to provide additional outlets, it is desirable to have couplers which can join sections of existing pipe at the point where a leak, for example, has occurred or where it is desired to add additional pipe thereto and which can be incorporated to seal the joint between the pipe sections effectively without disturbing to any substantial extent the existing pipe.
The prior art includes pipe coupling such as that shown in U.S. Pat. No. 4,109,944--Curtin, wherein the coupling is formed of two semicylindrical members arranged to enclose the pipe sections at the junction of the pipe sections so as to provide a water-tight seal. In the form shown in the aforementioned patent the coupling members are made of plastic and are designed to be adhesively-bonded to each other and to the pipe sections by a suitable cement. The two coupling members are formed to provide interlocking elements.
While the device of the aforementioned patent provides an adequate seal under normal conditions, pipes may be subjected to conditions which could rupture a simple seal such as that discussed above. For example, in some cases the pipes may be subjected to extreme changes in temperature which place a strain on bonded junctions of the coupler or they may be subjected to extreme changes in pressure which cause pipe vibration and impose a strain on the bonded junctions.
By the present invention a coupler is provided which has additional strength so that it can effectively resist even extreme changes in temperature or pressure and the resulting strain on the bonded junctions.
It is an object of the present invention, therefore, to provide an improved coupler for repairing broken pipes or adding to existing pipes, particularly where the existing pipe is relatively inaccessible and is difficult or impossible to remove and replace.
It is a further object of this invention to provide an improved coupler for repairing broken pipes or adding to existing pipes, which coupler has additional strength to prevent leakage under conditions of extreme changes in pressure which cause vibrations of the pipe or under conditions of extreme changes of temperature.